#70: Slam shield

Some people just don’t have much ‘mechanical sympathy,’ ie a sense of how hard to push or twist or bend a device to achieve some result. Especially when closing car doors, it’s common practice to use the ‘stand back and slam’ approach. This is bad because:

  • It encourages people to make a bloody nuisance of themselves in the early hours: “HOWDY NEIGHBOURS, WE’VE BEEN TO A PARTY”
  • The door takes a terrible mechanical beating over the course of its lifetime.
  • Most important of all, It’s still too easy to catch some poor child’s fingers in the gap

I’m not advocating an MIB II complex electronic door closure system -which is guaranteed to break (replacement cost £2,299 + VAT, per door, thanks).

Instead, todays’s invention take the form of a hose fitted around the internal periphery of a car door, to form a loop (you could use a hollow version of the common foam door seal).

One end of the loop has compressed air passed in when the door starts shutting (it could be compressed by the previous door closure action). The other end of the hose has a microphone embedded in it. The microphone ‘knows’ the sound of a correctly closing door. Children’s fingers depressing the hose, by being in the gap, and other phenomena, such as hurling the door closed, make a discernibly different noise within the hose and cause the door’s internal rubber stops rapidly to protrude -or not to withdraw. (This whistling hosepipe technique might also underpin the contact monitoring pads of this idea).

If you wanted a greater margin of safety, the hose might have pinholes inserted along its length which would issue compressed air streams. These would interact with objects in the gap but not actually in contact with the hose, changing slightly the noise picked up by the microphone and stopping the door from closing somewhat earlier.

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